 Classes of trains  Fundamental principles of track authority  Impact of power/ton ratios  Drivers of dispatch priority 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida1

 A train is a locomotive or locomotives, with or without cars, and displaying markers  Track is a fixed guideway that trains must follow  Two trains shall not occupy a track location at the same time  Must protect track maintenance machines and workers from trains 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida2

 Prevent collisions  Train-train  Train-mw forces  Accommodate overall traffic demand  Avoid unnecessary delay  Meet service requirements  Minimize train operating costs 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida3

 Facilitate train meets and overtakes  Maintain safe spacing between trains  Prevent route conflicts  Protect maintenance workers/equipment  Enforce track speed limits*  Alert trains to hazards (e.g., broken rails)*  Enforce authority limits * 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida4 * Provided by some types of systems

 Occupancy: presence of a train or work crew on a track location or section  Authority: permission for a train or work crew to occupy a track  Authority limits: track boundary within which authority is granted (may be directional)  Controlled track: authority granted by a dispatcher, control operator, or procedure  Non-controlled track: authority not required; train crews must avoid conflicting movements 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida7

 Signal-controlled operation  Proceed indication  wayside absolute signal  cab signal  Written or verbal order from dispatcher  permitting train to pass restricting absolute signal  permitting maintenance force to occupy track section  Non signal-controlled operation  Timetable modified as needed by train orders  Written or verbal order from dispatcher

 Operating Rules (e.g., GCOR, Norac)  Employee timetables  Train bulletins  Fixed wayside signs (e.g., mileposts, block boundaries)  Signal hardware  Voice radio systems  Data radio systems

 Time based  Distance based 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida10 Distance Time Minimum Time Separation Distance Time Blocks Block occupancy time

 Overlap occurs when two trains have simultaneous authority to use a given track segment  May be permissible if trains are traveling in same direction  Never allowable for trains moving in opposite directions 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida11 Must protect against following movements

Operating Authority Operating Authority Operating Authority Operating Authority

 Passenger  Intercity  High-speed corridor  Long-haul  Regional  Commuter  Express  Local  Freight  Intermodal  Manifest  Unit train  Loaded  Empty  Local  Company service

Train typeLength (ft) Max. Speed (mph)HP/ton Weight (tons) Intermodal ~ Manifest freight Bulk commodity Local freight Long-haul intercity Regional intercity Commuter High-speed corridor September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida14

 The power/weight ratio is an important factor in train performance  Maximum speed achievable  Acceleration characteristics (time, distance to reach desired speed)  Deceleration on ascending grades  Can alter by adjusting power or train weight  Higher value permits better performance, but generally at greater operating cost  Railroad provides sufficient HP to suit service needs 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida15

P/W = 0.5 P/W = 1.0 P/W = 1.5

 All trains do not perform equally  Acceleration/deceleration  Maximum speed  All trains are not the same length  Meet/pass locations are not equally spaced  All trains are not equally important  Schedule sensitivity  Revenue contribution  Traffic is subject to peaks and valleys  Track requires outages for maintenance 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida20

 Designate train priority in scheduling and dispatching  Explicit  Formal aspect of control system  Regular trains (scheduled) receive class designation (1 st, 2 nd, 3 rd, etc.)  Occupancy prioritized by train order, train class, and direction  Implicit  Not formal aspect of control system  Occupancy prioritized by factors like train schedule sensitivity, revenue contribution, and operating performance 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida21

1.High speed passenger 2.Conventional inter-city (corridor or long-haul) 3.Commuter express 4.Passenger deadheads 5.Intermodal 6.Manifest 7.Local commuter 8.Bulk unit train 9.Local freight

Traffic Direction Min. Train Separation

Traffic Direction Pass Delay